The media giant 21st Century Fox, the empire run by Rupert Murdoch, made an $80 billion takeover bid in recent weeks for Time Warner Inc. but was rebuffed.

The bold approach could put Time Warner in play and might again ignite a reshaping of the media industry, prompting a new spate of mega-mergers among the nation’s largest entertainment companies.

Murdoch has built a global media juggernaut over nearly five decades spanning studios, television channels and newspapers, in part, by pursuing bold deals that were often rebuffed at first by the targets of his overtures, only to later acquiesce.

Time Warner on Wednesday confirmed that it had rejected a cash and stock offer from Twenty-First Century, saying that it was not in the company’s best interests. The Time Warner statement pointed to its own strategic plan, what it said was “uncertainty” over the value of Twenty-First century stock and regulatory risks as among the reasons for its rebuff.

The company said that Twenty-First Century Fox had offered 1.531 of its Class A non-voting common shares and $32.42 in cash for every Time Warner share — or a total of nearly $86.30, a premium of roughly 22 per cent to Time Warner’s closing price on Tuesday.

Earlier on Wednesday, 21st Century Fox also confirmed that it had made a formal offer to Time Warner last month. “The Time Warner board of directors declined to pursue our proposal,” the statement said. “We are not currently in any discussions with Time Warner.”

Together, 21st Century Fox and Time Warner would become a colossus with an array of television networks and channels like Fox, Fox News, FX, TNT and TBS; the premium subscription channel HBO, movie studios like 20th Century Fox, Warner Bros. and other prominent outlets. It would also combine Fox’s growing sports business with the broadcast rights that Time Warner owns for professional and college basketball and Major League Baseball, among other sports.

The combined company would have total revenue of $65 billion.

As part of the proposal to buy Time Warner, people briefed on the proposal said, 21st Century Fox indicated that it would sell CNN to head off potential antitrust concerns since Fox News competes directly with CNN.

Putting CNN on the auction block would likely stir up a bidding war for the news channel; both CBS and ABC, a unit of the Walt Disney Company, have long been viewed as interested suitors.

The company first approached Time Warner in early June, these people said. Chase Carey, the president of 21st Century Fox and a longtime top lieutenant to Murdoch, met privately with Time Warner’s chief executive, Jeff Bewkes, these people said. 21st Century Fox said it would raise $24 billion to help pay for the deal and stressed that its bid was not dependent on financing.

The company estimated that a combination would create $1 billion in cost savings and possibly more, primarily by cutting sales staff and back-office functions, these people said.